1. Field of the Invention
This invention relates to a process for efficient, batchwise, electroless metal plating of aramid fibers wherein the metal is strongly adhered to the aramid fiber substrate and provides a highly conductive surface.
2. Description of the Prior Art
Electroless plating is the deposition of a metal film by interaction of metal ions and a chemical reducing agent in a basic solution. Electroless plating, in a general way, is well known. One of the difficulties in achieving successful electroless plating has resided in obtaining good adhesion between the plating substrate and the plated metal. While mere encapsulation may suffice for some applications and some articles, good adhesion of the plated metal is essential for fiber surfaces because the plated metal coating must be durable enough to withstand the forces of further processing and end use stresses.
U.S. Pat. No. 5,302,415, issued Apr. 12, 1994, discloses a process for making electroless plated aramid surfaces by means of a preplating treatment using 80 to 90 weight percent aqueous sulfuric acid.
U.S. Ser. No. 08/261,074, which is commonly assigned discloses a process for plating aramid surfaces by using nitric acid or chlorosulfonic or fluorosulfonic acid as preplating treatment materials.
U.S. Pat. No. 4,042,737 discloses a process for the production of crimped, metal coated continuous filament yarns suitable for making antistatic fabrics by knitting the yarn, depositing a metal coating on the yarn, and then deknitting the yarn. There is indication that, while the coating is not uniform along the length of the yarn, it is adequately conductive to supply antistatic qualities for the purposes intended therein.